Cooling of internal combustion engine



Dec. 24, 1940. Q o, TQWLER 2,225,807

COOLING OF INTERNAL COMBUSTION ENGINE Filed Jan. 4, 1940 12 15 g 11 I618 I Patented Dec. 24, 1940 UNITED STATES COOLING OF INTERNAL COMBUSTIONENGINE Clifford Owen Towler, Rochester, England, as-

signor to Pobioy Airmotors & Aircraft Limited, Rochester, Kent, EnglandApplication January 4, 1940, Serial No. 312,426 In Great Britain January24, 1939 3 Claims.

In an internal combustion engine the heat which the material of thecylinders takes up from the burning gas requires to be dissipated.

This is in some cases effected by means or water 5 or other liquidsurrounding the cylinders, cylinder heads and ports, while in otherinstances the cooling is effected by means of air and the cylinders andcylinder heads are provided with external fins in order to expose asufficient surface' to the cooling air.

In all engines deleterious effects are produced when the temperature ofthe interior walls of the cylinder exceeds a certain value. Heat istransmitted from the burning gases to the cyl-1 inder barrel, cylinderhead and exhaust passage in the cylinder head or barrel. Some of theheat generated by the explosions occurring in the cylinder istransmitted to the cylinder and cylinder head through the walls of thecylinder and combustion chamber, and also through the walls of theexhaust port and passage- It has been proposed to reduce the quantity ofheat which is so transferred to the cylinder head or barrel byprovidingthe exhaust passage with a lining of a material of low thermalconductivi-ty, such as asbestos", and also to provide over the lining asleeve of heat-resisting material to assist in retaining the insulatinglining in position. 7 30 It is a matter of considerable difllculty toretain the insulating lining securely in the exhaust passage of thecylinder, and according. to the invention this difllculty is overcome bymaking the lining an integral part of the cylinder head. This is done byincorporating it in the mould in which the cylinder is to be cast andcasting the material of the cylinder around it. In the case where thelining consists of asbestos, it is desirable to support it by means ofa'sleeve of heat-resisting material, to the external surfaceoi which thelining is applied, in which case the sleeve and lining are incorporatedin'the mould as a unit, but the use of such a supporting sleeve is notessential in all cases.

45 In an engine constructed in accordance with the invention, thequantity of heat transmitted from the exhaust gases to the-material orthe size of radiator necessary. In aircraft engines this will decreasethe drag of the aircraft, and consequently improve the performance ofsuch aircraft. p

In air cooled aircraft engines the necessary amount of cooling air willbe reduced with a consequent reduction in drag, and increasedperformance of the aircraft.

One form of cylinder constructed in accordance with the invention willnow be described 5 in further detail, by way of example, with referenceto the accompanying drawing, in which:

Fig. l is a side elevation of the sleeve for supporting the insulatinglining;

Fig. 2 is the corresponding end elevation;

Fig. 3 is a section along the line III III in Fig.2;

Fig. 4 is a similar section through the sleeve 7 after coating with theinsulating lining, and

Fig. 5 is a ,vertical section through the cylinder head.

The cylinder head In is formed with an inlet passage H and an exhaustpassage l2,'the inlet valve l3 and exhaust valve It being shown aspoppet valves of conventional construction.

The exhaust passage I2 is provided with an .the paste to the sleeve andbaking in an oven until the coating has'set. When perfectly dry theassembly is used as a core in the mould in which the cylinder head iscast. On account of the projecting flanges of the sleeve, which becomeembedded in'the metal of the casting,

there is no risk of displacement of the sleeve or coating.

Although the drawing illustrates the application of the invention to acylinder having P ppet valves, it should be understood that itis alsoapplicable to sleeve valve engines, and indeed to the exhaust ports ofall types of internal combustion engines.

What I claim as my invention and desire to secure by Letters Patent is:

1. In a cylinder for an internal combustion engine having an exhaustport and passage, a heat insulating lining which forms a unitary part ofthe structure of the exhaust passage, said unitary part being integrally'united with the material of the cylinder.

2. In a cylinder for an internal combustion engine having an exhaustport, a heat insulating unit which forms a unitary part of the structureof, and is retained in position in the exhaust passage, said unitarypart being integrally united with said cylinder, said unit consisting ofa sleeve of heat-resisting material, and a layer of heat insulatingmaterial disposed on the external surface or the sleeve andconstituting-an insulating lining for the walls 01 i 10 the exhaustpassage.

3. In a cylinder for an internal combustion engine having an exhaustport, a heat insulating unit which forms a unitary part of the structure01', and is retained in position in the exhaust passage, said unitarypart being integrally united with said cylinder, said unit consisting ofa sleeve of heat-resisting material, and a layer of asbestos. disposedon the external surface 01' the sleeve and constituting an insulatinglining for the wallspf the exhaust passage.

CLIFFORD OWEN TO W LER.

